1. Field of the Invention
The present invention relates to video playback apparatuses and display control methods, and more specifically relates to a video playback apparatus and a display control method in which the display is turned on only when necessary and is otherwise turned off.
2. Description of the Related Art
When a display device is turned on while music recorded on a disc, such as a compact disc (CD), is being played back, a high-frequency digital signal from a central processing unit (CPU) which controls the display of the display device is superimposed on an audio signal path. Therefore, the signal-to-noise (S/N) ratio of the audio signal decreases and the sound quality degrades. Accordingly, Japanese Examined Patent Application Publication No. 6-105532 discloses a disc player which includes a switch for stopping the operation of a display device while the music is being played back and which turns off the display during playback so as to prevent noise. In acoustic devices, such a function to improve the sound quality by turning off the display while sound is being played back by an audio signal is called a “blackout” function (function to turn off the display).
If a recording medium such as a CD is not such that an operation menu is to be displayed, continuous playback or the like is not affected even when a display function (or circuit for the display) is turned off. Accordingly, there is no problem in enabling the blackout function as necessary and turning off the display while the music is being played back. For example, when a user wishes to listen to the music with a high sound quality, the blackout function can be enabled and the display can be turned off. In addition, when a user wishes to only listen to the music from a DVD-Video disc of a live performance like listening to a CD since he or she has already seen the video enough, the blackout function can also be enabled and the display can be turned off.
On the other hand, in some DVD-Video discs, a menu screen is displayed first when playback thereof is started by a player, and playback does not start unless a certain menu is selected. Menus shown on the menu screen are, for example, a title menu for selecting a title and starting playback, an audio stream (audio track) selection menu, a subpicture selection menu, a menu for selecting the angle from which a video is to be played back, etc.
In the case in which the recording medium is such that the above-described menu screen is to be displayed, if the blackout function is activated and the display is turned off, the menu screen cannot be displayed and menu selection cannot be performed. Accordingly, playback cannot be started. In addition, since the menu screen is shown not only in the beginning but also in the middle of playback, the display cannot be controlled such that it is turned on only in the beginning and turned off afterwards.
Therefore, in discs such as DVD-Video/DVD-Audio discs which display the menu screen (playback does not start unless selection is performed) and start playback after receiving an operation command corresponding to the selected menu, there is a problem in that the user cannot perform menu selection and the following operations cannot be performed if the display function is simply turned off.